The primary goal of the Structure of Steroids Project is to contribute to a molecular level understanding of the biological and physiological events surrounding steroid synthesis, function and metabolism in natural and neoplastic processes. As a better understanding of these processes is achieved, rational drug design and endocrine therapy can contribute to the control of cancer and other diseases that are demonstrably endocrine related. The immediate goals of the project have been to generate, assemble and analyze structural data on steroid hormones, to publish a compendium of these data in the Atlas of Steroid Structure, and actively to stimulate interdisciplinary programs using data from X-ray crystal structure analysis to interpret biochemical, biophysical and physiological actions of steroids. Volume I of the Atlas of Steroid Structure will be published in the spring of 1975. The publication provides the occasion for a symposium bringing together scientists involved in the field of steroid-protein interactions on the one hand and those working in the area of steroid structure on the other. In recent years great strides have been made in understanding the mechanism of steroid-protein interactions at the molecular level in both normal and neoplastic processes. The time has clearly come when the results of many years of structural research can be applied to elucidate the finer details of these interactions. The symposium will be held in Buffalo on October 23rd and 24th, 1975.